.\" -*- nroff -*- generated from .Rd format
.BG
.FN SSasympOff
.TL
Asymptotic Regression Model with an Offset
.DN
This `selfStart' model evaluates an alternative parameterization
of the asymptotic regression function and the gradient with respect to
those parameters. It has an `initial' attribute that creates
initial estimates of the parameters `Asym', `lrc', and
`c0'. 
.CS
SSasympOff(input, Asym, lrc, c0)
.RA
.AG input
a numeric vector of values at which to evaluate the model.
.AG Asym
a numeric parameter representing the horizontal asymptote on
the right side (very large values of `input').
.AG lrc
a numeric parameter representing the natural logarithm of
the rate constant.
.AG c0
a numeric parameter representing the `input' for which the
response is zero.
.RT
a numeric vector of the same length as `input'.  It is the value of
the expression `Asym*(1 - exp(-exp(lrc)*(input - c0)))'.  If all of
the arguments `Asym', `lrc', and `c0' are names of objects, the
gradient matrix with respect to these names is attached as an
attribute named `gradient'.

.SA
`nls', `selfStart'
.EX
CO2.Qn1 <- CO2[CO2$Plant == "Qn1", ]
SSasympOff( CO2.Qn1$conc, 32, -4, 43 )  # response only
Asym <- 32
lrc <- -4
c0 <- 43
SSasympOff( CO2.Qn1$conc, Asym, lrc, c0 ) # response and gradient
.KW models
.WR
